/*
* Copyright (c) 2006-2007 Erin Catto http:
*
* This software is provided 'as-is', without any express or implied
* warranty.  In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked, and must not be
* misrepresented the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
// p = attached point, m = mouse point
// C = p - m
// Cdot = v
//      = v + cross(w, r)
// J = [I r_skew]
// Identity used:
// w k % (rx i + ry j) = w * (-ry i + rx j)
// var b2MouseJoint = Class.create();
// Object.extend(b2MouseJoint.prototype, b2Joint.prototype);
// Object.extend(b2MouseJoint.prototype,
import b2Mat22 from '../../common/math/b2Mat22';
import b2Vec2 from '../../common/math/b2Vec2';
import b2Math from '../../common/math/b2Math';
import b2Joint from './b2Joint';
import b2JointNode from './b2JointNode';
import b2Settings from '../../common/b2Settings';
export default class b2MouseJoint extends b2Joint {
    //--------------- Internals Below -------------------
    constructor(def) {
        super(def);
        // Presolve vars
        this.K = null;
        this.K1 = null;
        this.K2 = null;
        this.m_localAnchor = null;
        this.m_target = null;
        this.m_impulse = null;
        this.m_ptpMass = null;
        this.m_C = null;
        this.m_maxForce = 0;
        this.m_beta = 0;
        this.m_gamma = 0;
        // The constructor for b2Joint
        // initialize instance variables for references
        this.m_node1 = new b2JointNode();
        this.m_node2 = new b2JointNode();
        //
        this.m_type = def.type;
        this.m_prev = null;
        this.m_next = null;
        this.m_body1 = def.body1;
        this.m_body2 = def.body2;
        this.m_collideConnected = def.collideConnected;
        this.m_islandFlag = false;
        this.m_userData = def.userData;
        //
        // initialize instance variables for references
        this.K = new b2Mat22();
        this.K1 = new b2Mat22();
        this.K2 = new b2Mat22();
        this.m_localAnchor = new b2Vec2();
        this.m_target = new b2Vec2();
        this.m_impulse = new b2Vec2();
        this.m_ptpMass = new b2Mat22();
        this.m_C = new b2Vec2();
        //
        //super(def);
        this.m_target.SetV(def.target);
        //this.m_localAnchor = b2Math.b2MulTMV(this.m_body2.m_R, b2Math.SubtractVV( this.m_target, this.m_body2.m_position ) );
        var tX = this.m_target.x - this.m_body2.m_position.x;
        var tY = this.m_target.y - this.m_body2.m_position.y;
        this.m_localAnchor.x = (tX * this.m_body2.m_R.col1.x + tY * this.m_body2.m_R.col1.y);
        this.m_localAnchor.y = (tX * this.m_body2.m_R.col2.x + tY * this.m_body2.m_R.col2.y);
        this.m_maxForce = def.maxForce;
        this.m_impulse.SetZero();
        var mass = this.m_body2.m_mass;
        // Frequency
        var omega = 2.0 * b2Settings.b2_pi * def.frequencyHz;
        // Damping coefficient
        var d = 2.0 * mass * def.dampingRatio * omega;
        // Spring stiffness
        var k = mass * omega * omega;
        // magic formulas
        this.m_gamma = 1.0 / (d + def.timeStep * k);
        this.m_beta = def.timeStep * k / (d + def.timeStep * k);
    }
    static Create(def) {
        return new b2MouseJoint(def);
    }
    GetAnchor1() {
        return this.m_target;
    }
    GetAnchor2() {
        var tVec = b2Math.b2MulMV(this.m_body2.m_R, this.m_localAnchor);
        tVec.Add(this.m_body2.m_position);
        return tVec;
    }
    GetReactionForce(invTimeStep) {
        //b2Vec2 F = invTimeStep * this.m_impulse;
        var F = new b2Vec2();
        F.SetV(this.m_impulse);
        F.Multiply(invTimeStep);
        return F;
    }
    GetReactionTorque(invTimeStep) {
        //NOT_USED(invTimeStep);
        return 0.0;
    }
    SetTarget(target) {
        this.m_body2.WakeUp();
        this.m_target = target;
    }
    PrepareVelocitySolver() {
        var b = this.m_body2;
        var tMat;
        // Compute the effective mass matrix.
        //b2Vec2 r = b2Mul(b.m_R, this.m_localAnchor);
        tMat = b.m_R;
        var rX = tMat.col1.x * this.m_localAnchor.x + tMat.col2.x * this.m_localAnchor.y;
        var rY = tMat.col1.y * this.m_localAnchor.x + tMat.col2.y * this.m_localAnchor.y;
        // this.K    = [(1/m1 + 1/m2) * eye(2) - skew(r1) * invI1 * skew(r1) - skew(r2) * invI2 * skew(r2)]
        //      = [1/m1+1/m2     0    ] + invI1 * [r1.y*r1.y -r1.x*r1.y] + invI2 * [r1.y*r1.y -r1.x*r1.y]
        //        [    0     1/m1+1/m2]           [-r1.x*r1.y r1.x*r1.x]           [-r1.x*r1.y r1.x*r1.x]
        var invMass = b.m_invMass;
        var invI = b.m_invI;
        //b2Mat22 this.K1;
        this.K1.col1.x = invMass;
        this.K1.col2.x = 0.0;
        this.K1.col1.y = 0.0;
        this.K1.col2.y = invMass;
        //b2Mat22 this.K2;
        this.K2.col1.x = invI * rY * rY;
        this.K2.col2.x = -invI * rX * rY;
        this.K2.col1.y = -invI * rX * rY;
        this.K2.col2.y = invI * rX * rX;
        //b2Mat22 this.K = this.K1 + this.K2;
        this.K.SetM(this.K1);
        this.K.AddM(this.K2);
        this.K.col1.x += this.m_gamma;
        this.K.col2.y += this.m_gamma;
        //this.m_ptpMass = this.K.Invert();
        this.K.Invert(this.m_ptpMass);
        //this.m_C = b.m_position + r - this.m_target;
        this.m_C.x = b.m_position.x + rX - this.m_target.x;
        this.m_C.y = b.m_position.y + rY - this.m_target.y;
        // Cheat with some damping
        b.m_angularVelocity *= 0.98;
        // Warm starting.
        //b2Vec2 P = this.m_impulse;
        var PX = this.m_impulse.x;
        var PY = this.m_impulse.y;
        //b.m_linearVelocity += invMass * P;
        b.m_linearVelocity.x += invMass * PX;
        b.m_linearVelocity.y += invMass * PY;
        //b.m_angularVelocity += invI * b2Cross(r, P);
        b.m_angularVelocity += invI * (rX * PY - rY * PX);
    }
    SolveVelocityConstraints(step) {
        var body = this.m_body2;
        var tMat;
        // Compute the effective mass matrix.
        //b2Vec2 r = b2Mul(body.m_R, this.m_localAnchor);
        tMat = body.m_R;
        var rX = tMat.col1.x * this.m_localAnchor.x + tMat.col2.x * this.m_localAnchor.y;
        var rY = tMat.col1.y * this.m_localAnchor.x + tMat.col2.y * this.m_localAnchor.y;
        // Cdot = v + cross(w, r)
        //b2Vec2 Cdot = body->m_linearVelocity + b2Cross(body->m_angularVelocity, r);
        var CdotX = body.m_linearVelocity.x + (-body.m_angularVelocity * rY);
        var CdotY = body.m_linearVelocity.y + (body.m_angularVelocity * rX);
        //b2Vec2 impulse = -b2Mul(this.m_ptpMass, Cdot + (this.m_beta * step->inv_dt) * this.m_C + this.m_gamma * this.m_impulse);
        tMat = this.m_ptpMass;
        var tX = CdotX + (this.m_beta * step.inv_dt) * this.m_C.x + this.m_gamma * this.m_impulse.x;
        var tY = CdotY + (this.m_beta * step.inv_dt) * this.m_C.y + this.m_gamma * this.m_impulse.y;
        var impulseX = -(tMat.col1.x * tX + tMat.col2.x * tY);
        var impulseY = -(tMat.col1.y * tX + tMat.col2.y * tY);
        var oldImpulseX = this.m_impulse.x;
        var oldImpulseY = this.m_impulse.y;
        //this.m_impulse += impulse;
        this.m_impulse.x += impulseX;
        this.m_impulse.y += impulseY;
        var length = this.m_impulse.Length();
        if (length > step.dt * this.m_maxForce) {
            //this.m_impulse *= step.dt * this.m_maxForce / length;
            this.m_impulse.Multiply(step.dt * this.m_maxForce / length);
        }
        //impulse = this.m_impulse - oldImpulse;
        impulseX = this.m_impulse.x - oldImpulseX;
        impulseY = this.m_impulse.y - oldImpulseY;
        //body.m_linearVelocity += body->m_invMass * impulse;
        body.m_linearVelocity.x += body.m_invMass * impulseX;
        body.m_linearVelocity.y += body.m_invMass * impulseY;
        //body.m_angularVelocity += body->m_invI * b2Cross(r, impulse);
        body.m_angularVelocity += body.m_invI * (rX * impulseY - rY * impulseX);
    }
    SolvePositionConstraints() {
        return true;
    }
}
b2Joint.Register(b2Joint.e_mouseJoint, b2MouseJoint.Create);
